[DocDB] New unit test to validate post split compactions and disk full scenarios.

[rthallamko3]

Jira Link: DB-6031

Description

We would need to add a unit test that validates if the post split compaction runs into out of disk issues, the parent tablet continues to remain functional.

Based on the internal discussion, if post split compaction fails with out of disk - we can’t split tablet further until it is fully compacted.

void Tablet::TriggerFullCompactionSync(rocksdb::CompactionReason reason) {
  TEST_PAUSE_IF_FLAG(TEST_pause_before_full_compaction);
  WARN_WITH_PREFIX_NOT_OK(
      ForceFullRocksDBCompact(reason),
      Format("$0: Failed tablet full compaction ($1)", log_prefix_suffix_, ToString(reason)));
}

Warning: Please confirm that this issue does not contain any sensitive information

• I confirm this issue does not contain any sensitive information.